How to study well English grammar?
My advice is to learn English grammar through books. You should read children's books and English books. If not, then you should buy bilingual funny books to read both entertainment and remember the grammar structure used inside. From there, learn, take notes to apply when needed.
And, what is your advice?
I Studied my English Grammar in School though i don't need to Push more because as long as i can understand english and can speak even not perfect pronunciation .My advice is to learn English grammar through books. You should read children's books and English books. If not, then you should buy bilingual funny books to read both entertainment and remember the grammar structure used inside. From there, learn, take notes to apply when needed.
And, what is your advice?
By doing loads of exercises, otherwise you're not going to actually understand the grammar.
at least this is not physical exercise ? 
For me the best way is to have a quick look on the rules and uses then reading, reading helps to deliver the rule quickly and then its easy to use the grammer in your english
Wha is rules? is there anything ? lol it is a legit question and advice not a competition or anything.